Automotive electric motor-generator

ABSTRACT

The present invention provides an automotive electric motor-generator that can achieve sufficient cooling of a radiating plate by ensuring a sufficient cooling airflow ventilation channel within limited axial or radial dimensions. 
     In the present invention, first and second radiating plates each form a fan shape, have N-channel power MOSFETs mounted thereto, and have a drain potential for the power MOSFETs. A first circuit board includes insert conductors that connect the power MOSFETs in series, and a second circuit board has insert conductors that are connected to source terminals of the power MOSFETs and that have negative potential. The first radiating plate, the second radiating plate, the first circuit board, and the second circuit board are disposed in a fan shape that is centered around a shaft so as to line up radially in a plane that is perpendicular to the shaft outside one axial end of a rear housing.

TECHNICAL FIELD

The present invention relates to an automotive electric motor-generatorthat has an internal control apparatus, that is mounted to a vehicle,and that has engine starting, assisting, and generating functions, andparticularly relates to reductions in size of a control apparatus thathas power semiconductor elements, as well as improvements in reliabilitythat include superior cooling, vibration resistance, and dielectricstrength.

BACKGROUND ART

In recent years, reductions in CO₂ emissions are being sought with aview to preventing global warming, and hybrid vehicles, idling-reducedvehicles, etc., are being developed in earnest. When connecting controlapparatuses and automotive electric motor-generators in such vehicles,wiring length is increased if the control apparatus and the automotiveelectric motor-generator are separated greatly. Because wiringresistance between the control apparatus and the automotive electricmotor-generator is thereby increased, increasing voltage drop, it hasbeen difficult to achieve desired torque characteristics, rotationalfrequencies, etc. Other problems have been increased weight, andincreased cost, etc., due to the increased wiring length.

In view of these conditions, an integrated control apparatus automotiveelectric motor-generator that includes semiconductor elements has beenproposed (see patent Literature 1, for example). This control apparatushas a construction that is constituted by three radiating plates thathave differing electric potentials. In order to satisfy coolingefficiency, the semiconductor elements and electrode plates areconfigured so as to be in a ratio that is greater than or equal to 5.

Patent Literature 1: Japanese Patent Laid-Open No. 2004-208487 (Gazette)

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

Space for installing automotive electric motor-generators inside enginecompartments is becoming extremely restricted. Thus, it is necessary toaim for size reductions in the overall construction of controlapparatuses that are mounted internally in automotive electricmotor-generators. On the other hand, because the quantity of heatgenerated by the semiconductor elements is particularly large in controlapparatuses, it has been necessary to suppress temperature increases inthe semiconductor elements by increasing the size of the radiatingplates. Thus, the radiating plates for cooling the semiconductorelements occupy a large portion of the volume of the control apparatusin conventional integrated control apparatus automotive electricmotor-generators.

In conventional integrated control apparatus automotive electricmotor-generators, a radiating plate that corresponds to an upper armswitching drain side on which N-channel semiconductor elements aremounted and a radiating plate that corresponds to a lower arm switchingdrain side are disposed so as to line up in a radial direction of arotating shaft, and in addition an electrode plate that has negativepotential is disposed one step below those radiating plates in an axialdirection of the rotating shaft.

Thus, in conventional integrated control apparatus automotive electricmotor-generators, because the two radiating plates that correspond tothe upper and lower arm switching drain sides and the electrode platethat has negative potential are arrayed in two layers axially, axialdimensions of the automotive electric motor-generator are increased.

Arraying the two radiating plates and the electrode plate in two layersaxially within limited axial dimensions makes it harder to ensuresufficient cooling airflow ventilation channels, making it difficult toensure sufficient cooling of the two radiating plates onto which aremounted the semiconductor elements that need to be cooled the most.

In conventional integrated control apparatus automotive electricmotor-generators, the radiating plate that corresponds to the upper armswitching drain side and the radiating plate that corresponds to thelower arm switching drain side are disposed so as to form two layersradially on a common plane that is perpendicular to the rotating shaftso as to fill all permissible space in the radial direction of theautomotive electric motor-generator. Thus, because the heat radiatingarea of the two radiating plates cannot be enlarged any further in theradial direction of the rotating shaft, it has been difficult to ensurethe desired heat radiating area of the two radiating plates within thelimited radial dimensions.

Cooling of these radiating plates is performed by cooling airflows thatarise due to rotation of a fan that is mounted to the rotor. However,because the two radiating plates are disposed on a common plane that isperpendicular to the rotating shaft so as to fill all permissible spacein the radial direction of the automotive electric motor-generator,there has not been sufficient heat exchange surface area for axial flowof the cooling airflows to pass through and cool the two radiatingplates. In addition, it has also been difficult to ensure sufficientventilation channel area for the cooling airflows to pass throughbetween the two radiating plates.

Furthermore, in addition to heat exchange surface area and ventilationchannel area also being problematic for radial flow of the coolingairflows to pass through and cool these radiating plates in a similarmanner to the axial flow that is described above, since the coolingairflows also rise in temperature due to heat being exchanged at theradiating plate that corresponds to the lower arm switching drain side,which is positioned at an upstream end, and then cool the radiatingplate that corresponds to the upper arm switching drain side, which ispositioned at a downstream end, another problem has been that theradiating plate that corresponds to the upper arm switching drain sidecannot be sufficiently cooled.

The present invention aims to solve the above problems and a firstobject of the present invention is to provide an automotive electricmotor-generator that can achieve sufficient cooling of a radiating plateby ensuring a sufficient cooling airflow ventilation channel withinlimited axial dimensions.

A second object of the present invention is to provide an automotiveelectric motor-generator that can increase cooling of first and secondradiating plates by making expansion of radial dimensions of theradiating plates possible within limited radial dimensions to ensure adesired heat radiating area on the radiating plates, and also enablingcooling airflows to flow radially over the two radiating plates withoutinterfering with each other.

Means for Solving the Problem

An automotive electric motor-generator according to the presentinvention includes: a motor that has: a rotor that is rotatably disposedinside a housing; a stator that is disposed so as to surround aradially-outer side of the rotor; and at least one fan that is fixed toan axial end surface of the rotor, the motor functioning as a generatorand as an electric motor; and a power semiconductor apparatus thatcontrols a current that is supplied to the motor. The powersemiconductor apparatus includes: a fan-shaped first radiating plate towhich a first switching element that is constituted by an N-channelsemiconductor element is mounted, and that has a drain potential for thefirst switching element; a fan-shaped second radiating plate to which asecond switching element that is constituted by an N-channelsemiconductor element is mounted, and that has a drain potential for thesecond switching element; a fan-shaped first circuit board in which afirst electrode member that connects the first switching element and thesecond switching element electrically in parallel is insert molded intoa first insulating resin; and a fan-shaped second circuit board in whicha second electrode member that is electrically connected to a sourceterminal of the second switching element and that has negative potentialis insert molded into a second insulating resin. In addition, the firstradiating plate, the second radiating plate, the first circuit board,and the second circuit board are disposed in a fan shape that iscentered around a shaft of the rotor so as to line up radially in aplane that is perpendicular to the shaft outside one axial end of thehousing.

An automotive electric motor-generator according to the presentinvention includes: a motor that has: a rotor that is rotatably disposedinside a housing; a stator that is disposed so as to surround aradially-outer side of the rotor; and at least one fan that is fixed toan axial end surface of the rotor, the motor functioning as a generatorand as an electric motor; and a power semiconductor apparatus thatcontrols a current that is supplied to the motor. The powersemiconductor apparatus includes: a fan-shaped first radiating platethat is disposed in a fan shape that is centered around a shaft of therotor in a plane that is perpendicular to the shaft outside a firstaxial end of the housing, to which a first switching element that isconstituted by an N-channel semiconductor element is mounted, and thathas a drain potential for the first switching element; and a fan-shapedsecond radiating plate that is disposed in a fan shape that is centeredaround the shaft in a plane that is perpendicular to the shaft of therotor between the first radiating plate and a first axial end surface ofthe housing, to which a second switching element that is constituted byan N-channel semiconductor element is mounted, and that has a drainpotential for the second switching element.

EFFECTS OF THE INVENTION

According to the present invention, because the first and secondradiating plates and the first and second circuit boards can be disposedin a single layer axially, axial dimensions of the power semiconductorapparatus are reduced, enabling sufficient cooling airflow ventilationchannels to be ensured even within limited axial dimensions. Desiredheat radiating area, i.e., heat exchange surface area, can also beensured in the first and second radiating plates. Thus, cooling of thefirst and second radiating plates is improved, enabling temperatureincreases in the first and second switching elements to be efficientlysuppressed.

According to the present invention, because the first and secondradiating plates can be disposed in two layers axially, it is possibleto enlarge the dimensions of the first and second radiating platesradially, enabling desired heat radiating area, i.e., heat exchangesurface area, to be ensured in the first and second radiating plateseven within limited radial dimensions. Because cooling airflows flowradially over two surfaces of the first radiating plate and two surfacesof the second radiating plate without interfering with each other, heatthat is generated by the first and second switching elements can beradiated effectively from the first and second radiating plates. Inaddition, in the radial flow of the cooling airflows, cooling airflowsin which temperature has been increased by exchanging heat at the firstradiating plate are not supplied to cool the second radiating plate,improving cooling by the first and second radiating plates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 1 of thepresent invention;

FIG. 2 is a circuit diagram for explaining operation of the automotiveelectric motor-generator according to Embodiment 1 of the presentinvention;

FIG. 3 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 1 of thepresent invention;

FIG. 4 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 1 of thepresent invention in a state in which a cover has been removed;

FIG. 5 is a plan that shows a control apparatus in the automotiveelectric motor-generator according to Embodiment 1 of the presentinvention;

FIG. 6 is a cross section that is taken along line A-A in FIG. 4 so asto be viewed in the direction of the arrows;

FIG. 7 is a cross section that is taken along line B-B in FIG. 4 so asto be viewed in the direction of the arrows;

FIG. 8 is a cross section that is taken along line C-C in FIG. 4 so asto be viewed in the direction of the arrows;

FIG. 9 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 2 of thepresent invention;

FIG. 10 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 2 of thepresent invention in a state in which a cover has been removed;

FIG. 11 is a plan that shows a control apparatus in the automotiveelectric motor-generator according to Embodiment 2 of the presentinvention;

FIG. 12 is a cross section that is taken along line D-D in FIG. 10 so asto be viewed in the direction of the arrows;

FIG. 13 is a cross section that is taken along line E-E in FIG. 10 so asto be viewed in the direction of the arrows;

FIG. 14 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 3 of thepresent invention;

FIG. 15 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 3 of thepresent invention;

FIG. 16 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 3 of thepresent invention in a state in which a cover has been removed;

FIG. 17 is a plan that shows a control apparatus in the automotiveelectric motor-generator according to Embodiment 3 of the presentinvention;

FIG. 18 is a cross section that is taken along line F-F in FIG. 16 so asto be viewed in the direction of the arrows;

FIG. 19 is a cross section that is taken along line G-G in FIG. 16 so asto be viewed in the direction of the arrows;

FIG. 20 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 4 of thepresent invention;

FIG. 21 is a circuit diagram for explaining operation of the automotiveelectric motor-generator according to Embodiment 4 of the presentinvention;

FIG. 22 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 4 of thepresent invention;

FIG. 23 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 4 of thepresent invention in a state in which a cover has been removed;

FIG. 24 is a plan that shows a control apparatus in the automotiveelectric motor-generator according to Embodiment 4 of the presentinvention;

FIG. 25 is a cross section that is taken along line A-A in FIG. 23 so asto be viewed in the direction of the arrows;

FIG. 26 is a cross section that is taken along line B-B in FIG. 23 so asto be viewed in the direction of the arrows;

FIG. 27 is a cross section that is taken along line C-C in FIG. 23 so asto be viewed in the direction of the arrows;

FIG. 28 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 5 of thepresent invention;

FIG. 29 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 5 of thepresent invention in a state in which a cover has been removed;

FIG. 30 is a plan that shows a control apparatus in the automotiveelectric motor-generator according to Embodiment 5 of the presentinvention;

FIG. 31 is a cross section that is taken along line D-D in FIG. 29 so asto be viewed in the direction of the arrows;

FIG. 32 is a cross section that is taken along line E-E in FIG. 29 so asto be viewed in the direction of the arrows;

FIG. 33 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 6 of thepresent invention;

FIG. 34 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 6 of thepresent invention;

FIG. 35 is a rear-end end elevation, as seen from the rear side, of theautomotive electric motor-generator according to Embodiment 6 of thepresent invention in a state in which a cover has been removed;

FIG. 36 is a plan that shows a control apparatus in the automotiveelectric motor-generator according to Embodiment 6 of the presentinvention;

FIG. 37 is a cross section that is taken along line F-F in FIG. 35 so asto be viewed in the direction of the arrows; and

FIG. 38 is a cross section that is taken along line G-G in FIG. 35 so asto be viewed in the direction of the arrows.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

FIG. 1 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 1 of thepresent invention, FIG. 2 is a circuit diagram for explaining operationof the automotive electric motor-generator according to Embodiment 1 ofthe present invention, and FIG. 3 is a rear-end end elevation, as seenfrom the rear side, of the automotive electric motor-generator accordingto Embodiment 1 of the present invention. FIG. 4 is a rear-end endelevation, as seen from the rear side, of the automotive electricmotor-generator according to Embodiment 1 of the present invention in astate in which a cover has been removed, FIG. 5 is a plan that shows acontrol apparatus in the automotive electric motor-generator accordingto Embodiment 1 of the present invention, FIG. 6 is a cross section thatis taken along line A-A in FIG. 4 so as to be viewed in the direction ofthe arrows, FIG. 7 is a cross section that is taken along line B-B inFIG. 4 so as to be viewed in the direction of the arrows, and FIG. 8 isa cross section that is taken along line C-C in FIG. 4 so as to beviewed in the direction of the arrows.

In FIGS. 1 through 3, a motor 60 that constitutes part of an automotiveelectric motor-generator 1 includes: a front housing 2 and a rearhousing 3 that are made of aluminum that have a plurality of airdischarge aperture ribs 2 a and 3 a; a shaft 5 that is rotatablysupported in the front housing 2 and the rear housing 3 by means of abearing 4; a rotor 6 that is fixed to the shaft 5; and a stator 9 thatis disposed so as to surround the rotor 6. The rotor 6 includes: a fieldwinding 7 that generates magnetic flux on passage of an excitationcurrent; and a pole core 8 that is disposed so as to cover the fieldwinding 7 and in which magnetic poles are formed by the magnetic flux.The stator 9 includes: a stator core 10 that is disposed so as to beheld between the front housing 2 and the rear housing 3 from two axialends so as to surround the rotor 6; and an armature winding 11 that isinstalled in the stator core 10. The armature winding 11 is configuredby wye-connecting (star-connecting) a U-phase coil, a V-phase coil, anda W-phase coil.

Fans 12 are welded onto two axial end surfaces of the pole core 8, and apulley 13 is fixed by a nut to an end portion of the shaft 5 thatprojects out through the front housing 2. A brush holder 14 is mountedto the rear housing 3 so as to be positioned radially outside an endportion of the shaft 5 that projects out through the rear housing 3.Brushes 15 are disposed inside the brush holder 14 so as to slide incontact with slip rings 16 that are mounted to the end portion of theshaft 5 that projects out through the rear housing 3. The excitationcurrent is supplied to the field winding 7 from outside by means of thebrushes 15 and the slip rings 16. In addition, a rotational positiondetecting sensor 17 for vector control during electric drive is disposedon an axial end of the shaft 5 that projects out through the rearhousing 3.

In addition to the motor 60 that is described above, a control apparatus30 that constitutes a power semiconductor apparatus is mounted to therear housing 3 in the automotive electric motor-generator 1 so as to bepositioned radially outside the end portion of the shaft 5 that projectsout through the rear housing 3.

A cover 18 is mounted onto the rear housing 3 so as to cover a controlcircuit board 20 to which a control circuit 19 is mounted, the controlapparatus 30, and the brush holder 14 so as to prevent external foreignmatter from entering. In addition, a plurality of air intake apertures18 a are disposed through end surfaces and side wall surfaces of thecover 18. Air intake apertures 2 b and 3 b are also disposed through endsurfaces of the front housing 2 and the rear housing 3 in a vicinity ofthe shaft 5, and air discharge apertures 2 c and 3 c are disposedthrough side surfaces of the front housing 2 and the rear housing 3.

As shown in FIG. 2, the control apparatus 30 includes: three upper arms31, 33, and 35 that are each configured by connecting three powerMOSFETs 37 in parallel; and three lower arms 32, 34, and 36 that areeach configured by connecting three power MOSFETs 38 in parallel. Thesources of the three power MOSFETs 37 that are connected in parallel inthe upper arm 31 are connected to the drains of the three power MOSFETs38 that are connected in parallel in the lower arm 32. The sources ofthe three power MOSFETs 37 that are connected in parallel in the upperarm 33 are connected to the drains of the three power MOSFETs 38 thatare connected in parallel in the lower arm 34. In addition, the sourcesof the three power MOSFETs 37 that are connected in parallel in theupper arm 35 are connected to the drains of the three power MOSFETs 38that are connected in parallel in the lower arm 36. The controlapparatus 30 is configured by connecting in parallel three sets of powerMOSFETs 37 and 38 that have been connected in series in this manner.Here, power MOSFETs 37 and 38 have been used for the semiconductorelements, but semiconductor elements such as Insulated Gate BipolarTransistors (IGBTs), etc., may also be used.

An intermediate point of the power MOSFETs 37 and 38 that are connectedin series in the upper arm 31 and the lower arm 32 are connected to anend portion of the U-phase coil of the armature winding 11 by means ofalternating-current wiring 21. An intermediate point of the powerMOSFETs 37 and 38 that are connected in series in the upper arm 33 andthe lower arm 34 are connected to an end portion of the W-phase coil ofthe armature winding 11 by means of the alternating-current wiring 21.An intermediate point of the power MOSFETs 37 and 38 that are connectedin series in the upper arm 35 and the lower arm 36 are connected to anend portion of the W-phase coil of the armature winding 11 by means ofthe alternating-current wiring 21. A capacitor 22 is also connected inparallel between the upper and lower arms so as to smooth voltagefluctuations that result from switching of the power MOSFETs 37 and 38.A positive terminal and a negative terminal of a battery 23 areelectrically connected to a positive electrode side and a negativeelectrode side, respectively, of the control apparatus 30 by means ofdirect-current wiring 24. Moreover, the negative electrode of theautomotive electric motor-generator 1 and the negative electrode of thebattery 23 may also be connected indirectly through separate positionson a vehicle frame, etc.

In an automotive electric motor-generator 1 that is configured in thismanner, the control circuit 19 controls switching operations in thecontrol apparatus 30. The control circuit 19 also controls a fieldcurrent control circuit 26 so as to adjust a field current that issupplied to the field winding 7 of the rotor 6. In addition, the controlcircuit 19 has an inverter function for electric motor operation of theautomotive electric motor-generator 1 and a rectifying function forpower generation.

Here, during starting of an engine, direct-current power is suppliedfrom the battery 23 to the control apparatus 30 by means of thedirect-current wiring 24. The control circuit 19 that is mounted to thecontrol circuit board 20 performs on-off control of the power MOSFETs 37and 38 of the control apparatus 30 so as to convert the direct-currentpower to three-phase alternating-current power. The three-phasealternating-current power is supplied to the armature winding 11 bymeans of the alternating-current wiring 21. Thus, a rotating magneticfield is imparted around the field winding 7 of the rotor 6 to which afield current is being supplied by the field current control circuit 26,driving the rotor 6 to rotate. Rotational torque from the rotor 6 istransmitted to the engine by means of the shaft 5, the pulley 13, and abelt (not shown) so as to ignite and start the engine.

Then, once the engine has been started, rotational torque from theengine is transmitted to the automotive electric motor-generator 1 bymeans of a crank pulley, the belt, and the pulley 13. Thus, the rotor 6is rotated, inducing a three-phase alternating-current voltage in thearmature winding 11. Then, the control circuit 19 performs on-offcontrol of the power MOSFETs 37 and 38 of the control apparatus 30 suchthat the three-phase alternating-current power that has been induced inthe armature winding 11 is converted into direct-current power, and issupplied to the battery 23, and an electric load 25, etc.

Next, configuration of the control apparatus 30 will be explained withreference to FIGS. 4 through 8.

A first radiating plate 39 is made of copper and has been electroplated,and is formed so as to have a shape that has: a flat base portion 39 athat has an approximate fan shape (a C shape); and flange portions 39 bthat are disposed so as to extend radially outward from a front surfaceof the base portion 39 a at four positions that include twocircumferential end portions of the base portion 39 a and portions thatdivide the base portion 39 a into three equal sectionscircumferentially. Nine N-channel power MOSFETs 37 are mounted to thefirst radiating plate 39 so as to line up in a single rowcircumferentially such that source terminals 37S and gate terminals 37Gface radially outward by connecting drains thereof to the front surface(a mounting surface) of the base portion 39 a using a lead-free solder.In addition, a plurality of ventilating apertures 51 a are disposed soas to pass through the base portion 39 a. Here, the power MOSFETs 37correspond to a first switching element.

A first circuit board 44 is prepared by insert molding six insertconductors 49 a through 49 f, and is formed so as to have a shape thathas: a base portion 44 a that has an approximate fan shape (a C shape)that is parallel to an outer circumference of the base portion 39 a ofthe first radiating plate 39; and flange portions 44 b that are disposedso as to extend radially outward from an outer circumferential surfaceof the base portion 44 a at four positions that include twocircumferential end portions of the base portion 44 a and portions thatdivide the base portion 44 a into three equal sectionscircumferentially. The base portion 44 a and the flange portions 44 bconstitute a first insulating resin. The base portion 44 a of the firstcircuit board 44 is disposed so as to be parallel to the outercircumference of the base portion 39 a of the first radiating plate 39,and the flange portions 44 b are disposed in close contact with rearsurfaces of the flange portions 39 b of the first radiating plate 39.Moreover, the insert conductors 49 a, 49 c, and 49 e correspond to afirst electrode member.

First through third radiating plate segments 41 through 43 are formed soas to have approximately identical sizes, are each made of copper andhave been electroplated, and are formed so as to have flat arc shapesthat are larger than the base portion 44 a of the first circuit board44. A plurality of ventilating apertures 51 b are disposed so as to passthrough the first through third radiating plate segments 41 through 43.In addition, three N-channel power MOSFETs 38 are mounted to each of thefirst through third radiating plate segments 41 through 43 so as to lineup in a single row circumferentially such that source terminals 38S andgate terminals 38G face radially outward by connecting drains thereof torespective surfaces (mounting surfaces) using a lead-free solder. Thefirst through third radiating plate segments 41 through 43 are arrayedin a single row circumferentially so as to constitute a second radiatingplate 40 that has an approximate fan shape (a C shape) that is largerthan the base portion 44 a of the first circuit board 44. Here, thepower MOSFETs 38 correspond to a second switching element. Apredetermined clearance is also configured between the base portion 44 aof the first circuit board 44 and the first through third radiatingplate segments 41 through 43.

A second circuit board 45 is prepared by insert molding six insertconductors 50 a through 50 f, and is formed so as to have an approximatefan shape (a C shape) that has: a base portion 45 a that is parallel toan outer circumference of the second radiating plate 40; and flangeportions 45 b that extend radially inward from a rear surface of thebase portion 45 a at four positions that include two circumferential endportions of the base portion 45 a and portions that divide the baseportion 45 a into three equal sections circumferentially. The baseportion 45 a and the flange portions 45 b constitute a second insulatingresin. Moreover, the insert conductors 50 a, 50 c, and 50 e correspondto a second electrode member.

The second circuit board 45 is disposed in an approximate fan shape soas to be centered around a central axis of the rear housing 3 such thatthe flange portions 45 b are placed in close contact with an end surfaceof the rear housing 3. The first through third radiating plate segments41 through 43 are also disposed so as to line up in an approximate fanshape so as to be centered around the central axis of the rear housing 3in close proximity to an inner circumferential side of the base portion45 a such that the mounting surfaces face axially outward and two endportions of each are placed on the flange portions 45 b. The mountingsurfaces of the first through third radiating plate segments 41 through43 are positioned in a common plane with the front surface of the baseportion 45 a. In addition, the first circuit board 44 is disposed suchthat the flange portions 44 b face the flange portions 45 b of thesecond circuit board 45 across the first through third radiating platesegments 41 through 43. The first radiating plate 39 is disposed suchthat the mounting surface of the base portion 39 a faces axiallyoutward, the flange portions 39 b are placed on the flange portions 44 bof the first circuit board 44, and the base portion 39 a is in closeproximity to an inner circumferential side of the base portion 44 a ofthe first circuit board 44.

The flange portions 39 b at three positions that are not at a secondcircumferential end portion of the first radiating plate 39, the flangeportions 44 b at three positions that are not at a secondcircumferential end portion of the first circuit board 44, firstcircumferential end portions of each of the first through thirdradiating plate segments 41 through 43, and the flange portions 45 b atthree positions that are not at a second circumferential end portion ofthe second circuit board 45 are stacked axially on each other andsecurely fastened integrally to the rear housing 3 by mounting bolts 47.In addition, an output terminal bolt 48 that constitutes an externaloutput terminal is mounted so as to pass through the flange portion 39 bat the second circumferential end portion of the first radiating plate39 from a rear surface side and project axially outward through thecover 18. A terminal 46 is interposed between a head portion of theoutput terminal bolt 48 and the flange portion 39 b. The flange portion44 b of the first circuit board 44 is interposed between the outputterminal bolt 48 and the third radiating plate segment 43 such that thetwo are in an insulated state.

Thus, except at their respective first and second circumferential endportions, the first through third radiating plate segments 41 through 43are separated from a wall surface of the rear housing 3 by a distanceequivalent to a thickness of the flange portions 45 b of the secondcircuit board 45 so as to form cooling airflow ventilation channels. Thebase portion 44 a of the first circuit board 44 is also disposed on aninner circumferential side of the first through third radiating platesegments 41 through 43 so as to ensure a predetermined clearancetherebetween. In addition, the base portion 39 a of the first radiatingplate 39 is disposed on an inner circumferential side of the baseportion 44 a of the first circuit board 44 in close contact therewith.The rear surface of the base portion 45 a of the second circuit board45, rear surfaces of the first through third radiating plate segments 41through 43, a rear surface of the base portion 44 a of the first circuitboard 44, and a rear surface of the base portion 39 a of the firstradiating plate 39 are positioned in a common plane. In other words, thebase portion 45 a of the second circuit board 45, the first throughthird radiating plate segments 41 through 43, the base portion 44 a ofthe first circuit board 44, and the base portion 39 a of the firstradiating plate 39 are disposed in an approximate fan shape that iscentered around a central axis of the shaft 5 so as to line upconcentrically in a radial direction in a common plane that isperpendicular to the central axis of the shaft 5.

Two of the insert conductors 49 a and 49 c are insert-molded into thefirst circuit board 44 such that first ends are exposed at a firstcircumferential end portion front surface of the first circuit board 44,and second end portions are exposed on surfaces in regions thatcorrespond to the source terminals 37S of the three power MOSFETs 37that constitute the upper arms 31 and 35, respectively. Two of theinsert conductors 49 b and 49 d are insert-molded into the first circuitboard 44 such that first ends are exposed at the first circumferentialend portion front surface of the first circuit board 44, and second endportions are exposed on surfaces in regions that correspond to the gateterminals 37G of the three power MOSFETs 37 that constitute the upperarms 31 and 35, respectively. Exposed surfaces of the second endportions of the insert conductors 49 a through 49 d are positioned in acommon plane with the mounting surface of the first radiating plate 39.The source terminals 37S and the gate terminals 37G of the three powerMOSFETs 37 that constitute the upper arms 31 and 35 are soldered to theexposed surfaces of the corresponding insert conductors 49 a through 49d.

Two of the insert conductors 49 e and 49 f are insert-molded into thefirst circuit board 44 such that first ends are exposed at a secondcircumferential end portion front surface of the first circuit board 44,and second end portions are exposed on surfaces in regions thatcorrespond to the source terminals 37S and the gate terminals 37G,respectively, of the three power MOSFETs 37 that constitute the upperarm 33. Exposed surfaces of the second end portions of the insertconductors 49 e and 49 f are positioned in a common plane with themounting surface of the first radiating plate 39. The source terminals37S and the gate terminals 37G of the power MOSFETs 37 that constitutethe upper arm 33 are soldered to the exposed surfaces of thecorresponding insert conductors 49 e and 49 f.

Respective insert conductors 49 a, 49 c, and 49 e branch off and areexposed on the rear surfaces of the flange portions 44 b at threepositions that do not include the second circumferential end portion ofthe first circuit board 44. The exposed surfaces of these insertconductors 49 a, 49 c, and 49 e are placed in close contact with andelectrically connected to the first radiating plate segment 41, thethird radiating plate segment 43, and the second radiating plate segment42, respectively, by the fastening force of the mounting bolts 47.

Similarly, in the second circuit board 45, two of the insert conductors50 a and 50 c are insert-molded into the second circuit board 45 suchthat first ends are exposed at first circumferential end portion frontsurface of the second circuit board 45, and second end portions areexposed on surfaces in regions of the base portion 45 a that correspondto the source terminals 38S of the three power MOSFETs 38 thatconstitute the lower arms 32 and 36, respectively. Two of the insertconductors 50 b and 50 d are insert-molded into the second circuit board45 such that first ends are exposed at the first circumferential endportion front surface of the second circuit board 45, and second endportions are exposed on surfaces in regions of the base portion 45 athat correspond to the gate terminals 38G of the three power MOSFETs 38that constitute the lower arms 32 and 36, respectively. The sourceterminals 38S and the gate terminals 38G of the three power MOSFETs 38that constitute the lower arms 32 and 36 are soldered to the exposedsurfaces of the corresponding insert conductors 50 a through 50 d.

Two of the insert conductors 50 e and 50 f are insert-molded into thesecond circuit board 45 such that first ends are exposed at a secondcircumferential end portion front surface of the second circuit board45, and second end portions are exposed on surfaces in regions of thebase portion 45 a that correspond to the source terminals 38S and thegate terminals 38G, respectively, of the three power MOSFETs 38 thatconstitute the lower arm 34. The source terminals 38S and the gateterminals 38G of the three power MOSFETs 38 that constitute the lowerarm 34 are soldered to the exposed surfaces of the corresponding insertconductors 50 e and 50 f.

Respective insert conductors 50 a and 50 c branch off and are exposed onthe rear surfaces of the flange portions 45 b at two positions at thefirst circumferential end portion of the second circuit board 45. Inaddition, an insert conductor 50 e branches off and is exposed on therear surfaces of the flange portions 45 b at two positions at the secondcircumferential end portion of the second circuit board 45. The exposedsurfaces of these insert conductors 50 a, 50 c, and 50 e are placed inclose contact with and electrically connected to the wall surface of therear housing 3 by the fastening force of the mounting bolts 47.

The control apparatus 30 that is configured in this manner is fastenedto the end surface of the rear housing 3 by the three mounting bolts 47so as to be disposed in an approximate fan shape radially outside theshaft 5. The control circuit board 20, to which the control circuit 19that includes elements such as custom ICs, drivers, etc., that controloperation of the power MOSFETs 37 and 38 is mounted, and the brushholder 14, into which the field current control circuit 26 and thecapacitor 22, etc., that control the field current to the field winding7 are integrated, are disposed in an approximately fan-shaped notchportion of the control apparatus 30.

The drains of the respective power MOSFETs 37 that constitute the upperarms 31, 33, and 35 are electrically connected to the output terminalbolt 48 by means of the first radiating plate 39 and are also led intothe brush holder 14 by means of the terminal 46. The source terminals38S of the respective power MOSFETs 38 that constitute the lower arms32, 34, and 36 are electrically connected to the rear housing 3 by meansof the insert conductors 50 a, 50 c, and 50 e.

The source terminals 37S of the respective power MOSFETs 37 thatconstitute the upper arms 31, 33, and 35 are electrically connected tothe first through third radiating plate segments 41 through 43,respectively, by means of the exposed surfaces of the insert conductors49 a, 49 c, and 49 e that are exposed on the rear surfaces of the flangeportions 44 b of the first circuit board 44. Output wires (thealternating-current wiring 21) of the U-phase coil, the V-phase coil,and the W-phase coil of the armature winding 11 are soldered to thefirst through third radiating plate segments 41 through 43,respectively.

The source terminals 37S and 38S and the gate terminals 37G and 38G ofthe power MOSFETs 37 and 38 are electrically connected to the controlcircuit 19 by means of the portions of the insert conductors 49 athrough 49 f and 50 a through 50 f that are exposed at thecircumferential end portions of the first and second circuit boards 44and 45.

Now, when the fan 12 at the rear end is driven to rotate together withthe rotation of the rotor 6, cooling airflows are sucked through the airintake apertures 18 a into the cover 18. The cooling airflows that havebeen sucked into the cover 18 then flow in through the air intakeapertures 3 b into the rear housing 3, are deflected centrifugally bythe fan 12, and are discharged through the air discharge apertures 3 c.

Here, the cooling airflows flow as indicated by arrows Fa through Fd inFIG. 1. Specifically, as indicated by the arrow Fa, a cooling airflowthat has flowed in through the air intake apertures 18 a that aredisposed through the end surface of the cover 18 flows radially inwardover the front surface of the base portion 39 a of the first radiatingplate 39, and flows toward the rear housing 3 by passing between thefirst radiating plate 39 and the shaft 5. As indicated by the arrow Fb,a portion of the cooling airflow that has flowed in through the airintake apertures 18 a that are disposed through the end surface of thecover 18 flows toward the rear housing 3 by flowing between the firstradiating plate 39 and the second radiating plate 40.

In addition, as indicated by the arrow Fc, a cooling airflow that hasflowed in through the air intake apertures 18 a that are disposedthrough the side surface of the cover 18 flows toward the rear housing 3by flowing between the first radiating plate 39 and the second radiatingplate 40. As indicated by the arrow Fd, a portion of the cooling airflowthat has flowed in through the air intake apertures 18 a that aredisposed through the side surface of the cover 18 flows radially inwardby flowing between the second radiating plate 40 and the wall surface ofthe rear housing 3. The cooling airflows that have flowed through therespective ventilation channels flow into the rear housing 3 through theair intake apertures 3 b, are deflected centrifugally by the fan 12, andare discharged through the air discharge apertures 3 c. The powerMOSFETs 37 and 38, the first and second radiating plates 39 and 40, andthe control circuit board 20, as well as the rear-end coil ends of thearmature winding 11 and the air discharge aperture ribs 3 a, are therebycooled.

When the fan 12 at the front end is driven to rotate, cooling airflowsare sucked in through the air intake apertures 2 b into the fronthousing 2. The cooling airflows that have been sucked into the fronthousing 2 are deflected centrifugally by the fan 12, and are dischargedthrough the air discharge apertures 2 c. Front-end coil ends of thearmature winding 11 and the air discharge aperture ribs 2 a are therebycooled.

According to Embodiment 1, because the first radiating plate 39, thefirst circuit board 44, the second radiating plate 40, and the secondcircuit board 45 are disposed in a single layer in an axial direction ofthe shaft 5, axial dimensions of the control apparatus 30 can bereduced, enabling reductions in the size of the automotive electricmotor-generator 1.

Because the axial dimensions of the control apparatus 30 can be reduced,sufficient cooling airflow ventilation channels can be ensured evenwithin constraints on limited axial dimensions in the automotivegenerator-motor 1, ensuring sufficient cooling of the first radiatingplate 39 and the second radiating plate 40 to which are mounted thepower MOSFETs 37 and 38, which require cooling the most. Desired surfacearea and volume can be ensured in the first and second radiating plates39 and 40 within the limited axial dimensions by disposing radiatingfins so as to extend axially from the first radiating plate 39 and thesecond radiating plate 40, etc.

With regard to radial flow of the cooling airflows, because the coolingairflows flow over two surfaces of the first radiating plate 39 and thesecond radiating plate 40 without interfering with each other, effectiveradiating is performed.

Because the cooling airflows flow over the two surfaces of the firstradiating plate 39, between the first radiating plate 39 and the secondradiating plate 40, and also over the two surfaces of the secondradiating plate 40 without being stopped, ventilation resistance isreduced, improving cooling and also enabling wind noise to be reduced.

Because the ventilating apertures 61 a and 51 b are formed so as to passthrough the first radiating plate 39 and the second radiating plate 40,cooling airflows that flow axially and radially flow through theventilating apertures 61 a and 51 b. Thus, because ventilationresistance is reduced, airflow rate can be increased, and wind noise canbe reduced.

Because a space is formed between the first radiating plate 39 and thesecond radiating plate 40, which have different electric potentials, andthe two are also partitioned off by the base portion 44 a of the firstcircuit board 44, i.e., an insulating member, foreign matter, andelectrically-conductive deposits, etc., will not accumulate, ensuringhighly-reliable insulation and also preventing the occurrence of leakagecurrents between the different electric potentials, and galvaniccorrosion, etc.

Because the output terminal bolt 48 projects axially outward from arear-end end portion of the automotive electric motor-generator 1,connecting wiring with the external components such as the battery 23,etc., is facilitated if space is present rearward in a vehicle.

Because the second radiating plate 40 is positioned radially outside thefirst radiating plate 39, electrical connection with the armaturewinding 11 of the stator 9 is facilitated.

Because the first and second radiating plates 39 and 40 and the firstand second circuit boards 44 and 45 are fastened integrally onto the endsurface of the rear housing 3 by the mounting bolts 47 in an assembledstate, highly-reliable vibration resistance is achieved.

The second radiating plate 40 is fixed to the end surface of the rearhousing 3 by means of the flange portions 45 b of the second circuitboard 45. Thus, because heat from the power MOSFETs 38 is conducted tothe rear housing 3 by means of the second radiating plate 40 and theflange portions 45 b, the power MOSFETs 38 can be cooled effectively.

The front surface of the base portion 45 a is positioned in a commonplane with the mounting surfaces of the first through third radiatingplate segments 41 through 43, the second end portions of the insertconductors 50 a through 50 f are exposed on the front surface of thebase portion 45 a at regions that correspond to the source terminals 38Sand the gate terminals 38G of the power MOSFETs 38, and the sourceterminals 38S and the gate terminals 38G of the power MOSFETs 38 aresoldered to the exposed surfaces of the corresponding insert conductors50 a through 50 f. Thus, the source terminals 38S and the gate terminals38G of the power MOSFETs 38 and the insert conductors 50 a through 50 fcan be connected directly and simply, making reductions in sizepossible.

The insert conductors 50 a, 50 c, and 50 e that are electricallyconnected to the source terminals 38S of the power MOSFETs 38 areinsert-molded into the second circuit board 45 so as to be exposed onthe rear surfaces of the flange portions 45 b, and are placed in contactwith the end surface of the rear housing 3 by the fastening force of themounting bolts 47. Thus, connecting electrode members that connect theinsert conductors 50 a, 50 c, and 50 e and the rear housing 3 are nolonger necessary, reducing the number of parts proportionately, andenabling weight, and cost, etc., to be reduced, and also simplifyingconnecting processes. In addition, because the rear housing 3 is used asground for the automotive electric motor-generator 1, electrode membersthat have negative potential are no longer necessary, reducing thenumber of parts, and enabling weight, and cost, etc., to be reduced.Because the source terminals 38S of the power MOSFETs 38 are connectedto the rear housing 3 by means of the insert conductors 50 a, 50 c, and50 e, heat from the power MOSFETs 38 is transferred to thelow-temperature rear housing 3 directly without air intervening,enabling temperature increases in the power MOSFETs 38 to be suppressed.

Now, because the flange portion 39 b for mounting the output terminalbolt 48 is disposed so as to extend radially outward from the baseportion 39 a of the first radiating plate 39 so as to be positioned onthe second radiating plate 40, the heat radiating area of the firstradiating plate 39 is reduced. Thus, it is desirable to make the radialwidth of the base portion 39 a of the first radiating plate 39 greaterthan the radial width of the base portion of the second radiating plate.Because the heat radiating area of the first radiating plate 39 isthereby increased, cooling of the first radiating plate 39 is preventedfrom deteriorating due to the output terminal bolt 48 being mounted.Thus, the cooling efficiency of the first radiating plate 39 becomesapproximately equal to the cooling efficiency of the second radiatingplate 39 and 40, enabling the power MOSFETs 37 and 38 that are mountedto the first and second radiating plates 39 and 40 to be cooled toapproximately identical temperatures. In addition, because rigidity ofthe first radiating plate 39 is increased, mechanical strength againstexternal forces from external connecting wires is improved. Thus, evenif external forces when external components such as the battery 23,etc., are connected to the output terminal bolt 48, or stresses thatresult from vibrating external forces, etc., act on the first radiatingplate 39, situations in which the first radiating plate 39 might breakare prevented.

Embodiment 2

FIG. 9 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 2 of thepresent invention, FIG. 10 is a rear-end end elevation, as seen from therear side, of the automotive electric motor-generator according toEmbodiment 2 of the present invention in a state in which a cover hasbeen removed, FIG. 11 is a plan that shows a control apparatus in theautomotive electric motor-generator according to Embodiment 2 of thepresent invention, FIG. 12 is a cross section that is taken along lineD-D in FIG. 10 so as to be viewed in the direction of the arrows, andFIG. 13 is a cross section that is taken along line E-E in FIG. 10 so asto be viewed in the direction of the arrows.

In FIGS. 9 through 13, a second circuit board 45A in a control apparatus30A is formed so as to have an approximate fan shape that has anL-shaped cross section that is constituted by a base portion 45 a and aflange portion 45 b. First through third radiating plate segments 41through 43 that constitute a second radiating plate 40 are arrayed in anapproximate fan shape, and are molded integrally with a second circuitboard 45A such that front surfaces and inner wall surfaces of each areexposed. The front surfaces of the first through third radiating platesegments 41 through 43 that have been arrayed in an approximate fanshape are positioned level with a front surface of the base portion 45 aof the second circuit board 45A, and the rear surfaces of the firstthrough third radiating plate segments 41 through 43 are covered by theflange portion 45 b.

Six insert conductors 50 a through 50 f are also insert-molded into thesecond circuit board 45A, but instead of being exposed on a rear surfaceof the flange portion 45 b, portions of the insert conductors 50 a, 50c, and 50 e extend radially outward from the base portion 45 a in avicinity of connecting protrusion portions 54 that are disposed so as toprotrude from an end surface of a rear housing 3. Projecting portions 52of the insert conductors 50 a, 50 c, and 50 e are respectively fastenedto the connecting protrusion portions 54 of the rear housing 3 by screws53.

Moreover, the rest of this embodiment is configured in a similar mannerto Embodiment 1 above.

In this automotive electric motor-generator 1A, the second circuit board45A and the first through third radiating plate segments 41 through 43are disposed on the rear housing 3 in an approximate fan shape so as tobe centered around the central axis of the rear housing 3. The firstcircuit board 44 is disposed such that the flange portions 44 b face theflange portion 45 b of the second circuit board 45A across the firstthrough third radiating plate segments 41 through 43. In addition, thefirst radiating plate 39 is disposed such that the flange portions 39 bare placed on the flange portions 44 b of the first circuit board 44 andthe base portion 39 a is in close proximity to an inner circumferentialside of the base portion 44 a of the first circuit board 44.

The flange portions 39 b at three positions that are not at a secondcircumferential end of the first radiating plate 39, the flange portions44 b at three positions that are not at a second circumferential endportion of the first circuit board 44, first circumferential ends ofeach of the first through third radiating plate segments 41 through 43,and the flange portion 45 b of the second circuit board 45A are stackedaxially on each other and securely fastened to the rear housing 3 bymounting bolts 47. In addition, the output terminal bolt 48 is mountedso as to pass through the flange portion 39 b at the secondcircumferential end of the first radiating plate 39 from a rear surfaceside and project axially outward through the cover 18. The projectingportions 52 of the insert conductors 50 a, 50 c, and 50 e are fastenedto the connecting protrusion portions 54 of the rear housing 3 by thescrews 53. A terminal 46 is interposed between a head portion of theoutput terminal bolt 48 and the flange portion 39 b. In addition,although not shown, the flange portion 44 b of the first circuit board44 is interposed between the output terminal bolt 48 and the thirdradiating plate segment 43 such that the two are in an insulated state.

In an automotive electric motor-generator 1A that is configured in thismanner, the flange portion 45 b is placed in close contact with the endsurface of the rear housing 3 around an entire circumferential region ofthe second circuit board 45A, and the control apparatus 30A is cooled byheat transfer through the flange portion 45 b of the second circuitboard 45A to the rear housing 3, in addition to the cooling airflows Fathrough Fc that are shown in FIG. 1.

In Embodiment 2, because the first radiating plate 39, the first circuitboard 44, the second radiating plate 40, and the second circuit board45A are also disposed in a single layer in an axial direction of theshaft 5, the axial dimensions of the control apparatus 30A can bereduced, enabling similar effects to those in Embodiment 1 above to beachieved.

Because the first radiating plate 39, the first circuit board 44, thesecond radiating plate 40, and the second circuit board 45A are disposedin a single layer in an axial direction of the shaft 5 in a similarmanner to Embodiment 1 above, ventilation resistance is also reduced,increasing the cooling airflow rate. Heat from the power MOSFETs 38 istransferred from the second radiating plate 40 to the rear housing 3 bymeans of the flange portion 45 b of the second circuit board 45A, and iscooled by the cooling airflows by means of the air discharge apertureribs 3 a. Thus, because the flow rate of the cooling airflows isincreased and the rate of heat transfer to the rear housing 3 is alsoincreased, the rate of heat exchange from the rear housing 3 isincreased by synergistic reinforcement of the two, suppressingtemperature increases in the control apparatus 30A.

Because the second radiating plate 40 (the first through third radiatingplate segments 41 through 43) and the second circuit board 45A areintegrated by molding, highly-reliable vibration resistance can beachieved, and the number of parts is also reduced, simplifying assembly.

The flange portion 45 b of the circuit board 45A is formed so as to havean approximate fan shape. Thus, heat from the power MOSFETs 38 istransferred to the low-temperature rear housing 3 directly through thesecond radiating plate 40 and the flange portion 45 b, suppressingtemperature increases in the power MOSFETs 38. The first radiating plate39, the second radiating plate 40, and the first and second circuitboards 44 and 45A are also securely fastened such that a wide area ofthe approximately fan-shaped flange portion 45 b is placed in contactwith the end surface of the rear housing 3, achieving even morehighly-reliable vibration resistance.

Moreover, in conventional techniques, the drains and sources (grounds)of the lower arms are not in a common plane, spatially requiringconnecting members for connection and leading to increases in size.However, in Embodiment 2, the projecting portions 52 of the insertconductors 50 a, 50 c, and 50 e extend outward from the base portion 45a in the vicinity of the connecting protrusion portions 54 of the rearhousing 3 at an approximately uniform height. Thus, the lengths of theprojecting portions 52 of the insert conductors 50 a, 50 c, and 50 e areshortened, facilitating connection between the projecting portions 52and the connecting protrusion portions 54. In other words, according toEmbodiment 2, large connecting members that were required inconventional techniques are no longer necessary, enabling reductions insize.

Embodiment 3

FIG. 14 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 3 of thepresent invention, FIG. 15 is a rear-end end elevation, as seen from therear side, of the automotive electric motor-generator according toEmbodiment 3 of the present invention, FIG. 16 is a rear-end endelevation, as seen from the rear side, of the automotive electricmotor-generator according to Embodiment 3 of the present invention in astate in which a cover has been removed, FIG. 17 is a plan that shows acontrol apparatus in the automotive electric motor-generator accordingto Embodiment 3 of the present invention, FIG. 18 is a cross sectionthat is taken along line F-F in FIG. 16 so as to be viewed in thedirection of the arrows, and FIG. 19 is a cross section that is takenalong line G-G in FIG. 16 so as to be viewed in the direction of thearrows.

In FIGS. 14 through 19, first through third radiating plate segments 41through 43 that constitute a second radiating plate 40 in a controlapparatus 30B are arrayed in an approximate fan shape (a C shape) aroundan outer circumference of a first radiating plate 39, and are moldedintegrally into a circuit board 55 together with the first radiatingplate 39. This circuit board 55 is formed so as to have an approximatefan shape (a C shape) that has: a base portion 55 a that has anapproximate fan shape (a C shape) that is parallel to an outercircumference of a base portion 39 a of the first radiating plate 39;flange portions 55 b that are disposed so as to extend radially outwardfrom an outer circumferential surface of the base portion 55 a at fourpositions that include two circumferential end portions of the baseportion 55 a and portions that divide the base portion 55 a into threeequal sections circumferentially; a base portion 55 c that has anapproximate fan shape (a C shape) that is parallel to an outercircumference of the second radiating plate 40; and a flange portion 55d that is disposed so as to extend radially inward from a rear surfaceof the base portion 55 c and is linked to a rear surface of the baseportion 55 a. The base portions 55 a and 55 c and the flange portions 55b and 55 d correspond to an insulating resin.

Outer circumferential wall surfaces of the first through third radiatingplate segments 41 through 43 are covered by the base portion 55 c, rearsurfaces are covered by the flange portion 55 d, inner circumferentialwall surfaces are covered by the base portion 55 a, and front surfacesof each are exposed so as to be positioned in a common plane with thebase portions 55 c. The flange portions 55 b extend outward from thebase portion 55 a onto the front surfaces of the first through thirdradiating plate segments 41 through 43 at the four circumferentialportions. In addition, an outer circumferential wall surface of thefirst radiating plate 39 is covered by the base portion 55 a. A firstcircuit board 44 and a second circuit board 45A are thereby configuredintegrally into the circuit board 55.

Moreover, the rest of this embodiment is configured in a similar mannerto Embodiment 2 above.

In a similar manner to Embodiment 2 above, six insert conductors 49 athrough 49 f are insert-molded into portions of this control apparatus30B that include the base portion 55 a and the flange portions 55 b, andsix insert conductors 50 a through 50 f are insert-molded into portionsthat include the base portion 55 c and the flange portion 55 d.

In this automotive electric motor-generator 1B, the first and secondradiating plates 39 and 40 that have been integrated by the circuitboard 55 are disposed on the rear housing 3 in an approximate fan shapeso as to be centered around the central axis of the rear housing 3. Theflange portions 39 b at three positions that are not at a secondcircumferential end of the first radiating plate 39, the flange portions55 b at three positions that are not at a second circumferential endportion of the circuit board 55, first circumferential ends of each ofthe first through third radiating plate segments 41 through 43, and theflange portion 55 d of the circuit board 55 are each securely fastenedto the rear housing 3 by mounting bolts 47. In addition, the outputterminal bolt 48 is mounted so as to pass through the flange portion 39b at the second circumferential end of the first radiating plate 39 froma rear surface side and project axially outward through the cover 18.The projecting portions 52 of the insert conductors 50 a, 50 c, and 50 eare fastened to the connecting protrusion portions 54 of the rearhousing 3 by the screws 53. A terminal 46 is interposed between a headportion of the output terminal bolt 48 and the flange portion 39 b.

In an automotive electric motor-generator 1B that is configured in thismanner, the control apparatus 30B is cooled by heat transfer through theflange portion 55 d of the circuit board 55 to the rear housing 3, inaddition to the cooling airflows Fa and Fc that are shown in FIG. 1.

In Embodiment 3, because the first radiating plate 39, the circuit board55, and the second radiating plate 40 are also disposed in a singlelayer in an axial direction of the shaft 5, similar effects to those inEmbodiment 2 above can be achieved.

Because the first radiating plate 39 and the second radiating plate 40(the first through third radiating plate segments 41 through 43) areintegrated by being molded together with the circuit board 55,highly-reliable vibration resistance can be achieved, and the number ofparts is also reduced, simplifying assembly. In addition, heat from thepower MOSFETs 37 and 38 is radiated by means of the insulating resin ofthe circuit board 55, improving thermal balance.

The first radiating plate 39, the second radiating plate 40, and thecircuit board 55 are also securely fastened such that a wide area of theapproximately fan-shaped flange portion 55 d is placed in contact withthe end surface of the rear housing 3, achieving even morehighly-reliable vibration resistance.

Moreover, in Embodiments 1 through 3 above, the upper arms 31, 33, and35 and the lower arms 32, 34, and 36 are explained as being eachconfigured by connecting three power MOSFETs 37 or 38 in parallel, butthe number of power MOSFETs 37 or 38 in parallel is not limited tothree, and can be appropriately set so as to correspond to the requiredoutput capacity of the automotive electric motor-generator and to themaximum capacity and permissible temperature of the semiconductorelements, etc., and the number of power MOSFETs 37 or 38 in parallel mayalso be two or four, for example, or single power MOSFETs 37 or 38 mayalso be used.

In Embodiments 1 through 3 above, the output terminal bolt 48 is mountedso as to project axially outward, but an output terminal bolt may alsobe mounted so as to project radially outward.

Embodiment 4

FIG. 20 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 4 of thepresent invention, FIG. 21 is a circuit diagram for explaining operationof the automotive electric motor-generator according to Embodiment 4 ofthe present invention, and FIG. 22 is a rear-end end elevation, as seenfrom the rear side, of the automotive electric motor-generator accordingto Embodiment 4 of the present invention. FIG. 23 is a rear-end endelevation, as seen from the rear side, of the automotive electricmotor-generator according to Embodiment 4 of the present invention in astate in which a cover has been removed, FIG. 24 is a plan that shows acontrol apparatus in the automotive electric motor-generator accordingto Embodiment 4 of the present invention, FIG. 25 is a cross sectionthat is taken along line A-A in FIG. 23 so as to be viewed in thedirection of the arrows, FIG. 26 is a cross section that is taken alongline B-B in FIG. 23 so as to be viewed in the direction of the arrows,and FIG. 27 is a cross section that is taken along line C-C in FIG. 23so as to be viewed in the direction of the arrows.

In FIGS. 20 through 22, a motor 160 that constitutes part of anautomotive electric motor-generator 101 includes: a front housing 2 anda rear housing 3 that are made of aluminum that have a plurality of airdischarge aperture ribs 2 a and 3 a; a shaft 5 that is rotatablysupported in the front housing 2 and the rear housing 3 by means of abearing 4; a rotor 6 that is fixed to the shaft 5; and a stator 9 thatis disposed so as to surround the rotor 6. The rotor 6 includes: a fieldwinding 7 that generates magnetic flux on passage of an excitationcurrent; and a pole core 8 that is disposed so as to cover the fieldwinding 7 and in which magnetic poles are formed by the magnetic flux.The stator 9 includes: a stator core 10 that is disposed so as to beheld between the front housing 2 and the rear housing 3 from two axialends so as to surround the rotor 6; and an armature winding 11 that isinstalled in the stator core 10. The armature winding 11 is configuredby wye-connecting (star-connecting) a U-phase coil, a V-phase coil, anda W-phase coil.

Fans 12 are welded onto two axial end surfaces of the pole core 8, and apulley 13 is fixed by a nut to an end portion of the shaft 5 thatprojects out through the front housing 2. A brush holder 14 is mountedto the rear housing 3 so as to be positioned radially outside an endportion of the shaft 5 that projects out through the rear housing 3.Brushes 15 are disposed inside the brush holder 14 so as to slide incontact with slip rings 16 that are mounted to the end portion of theshaft 5 that projects out through the rear housing 3. The excitationcurrent is supplied to the field winding 7 from outside by means of thebrushes 15 and the slip rings 16. In addition, a rotational positiondetecting sensor 17 for vector control during electric drive is disposedon an axial end of the shaft 5 that projects out through the rearhousing 3.

In addition to the motor 160 that is described above, a controlapparatus 130 that constitutes a power semiconductor apparatus ismounted to the rear housing 3 in the automotive electric motor-generator101 so as to be positioned radially outside the end portion of the shaft5 that projects out through the rear housing 3.

A cover 118 is mounted onto the rear housing 3 so as to cover a controlcircuit board 120 to which a control circuit 119 is mounted, the controlapparatus 130, and the brush holder 14 so as to prevent external foreignmatter from entering. In addition, a plurality of air intake apertures118 a are disposed through end surfaces and side wall surfaces of thecover 118. Air intake apertures 2 b and 3 b are also disposed throughend surfaces of the front housing 2 and the rear housing 3 in a vicinityof the shaft 5, and air discharge apertures 2 c and 3 c are disposedthrough side surfaces of the front housing 2 and the rear housing 3.

As shown in FIG. 21, the control apparatus 130 includes: three upperarms 131, 133, and 135 that are each configured by connecting four powerMOSFETs 37 in parallel; and three lower arms 132, 134, and 136 that areeach configured by connecting four power MOSFETs 38 in parallel. Thesources of the four power MOSFETs 37 that are connected in parallel inthe upper arm 131 are connected to the drains of the four power MOSFETs38 that are connected in parallel in the lower arm 132. The sources ofthe four power MOSFETs 37 that are connected in parallel in the upperarm 133 are connected to the drains of the four power MOSFETs 38 thatare connected in parallel in the lower arm 134. In addition, the sourcesof the four power MOSFETs 37 that are connected in parallel in the upperarm 135 are connected to the drains of the four power MOSFETs 38 thatare connected in parallel in the lower arm 136. The control apparatus130 is configured by connecting in parallel three sets of power MOSFETs37 and 38 that have been connected in series in this manner. Here, powerMOSFETs 37 and 38 have been used for the semiconductor elements, butsemiconductor elements such as Insulated Gate Bipolar Transistors(IGBTs), etc., may also be used.

An intermediate point of the power MOSFETs 37 and 38 that are connectedin series in the upper arm 131 and the lower arm 132 are connected to anend portion of the U-phase coil of the armature winding 11 by means ofalternating-current wiring 21. An intermediate point of the powerMOSFETs 37 and 38 that are connected in series in the upper arm 133 andthe lower arm 134 are connected to an end portion of the W-phase coil ofthe armature winding 11 by means of the alternating-current wiring 21.An intermediate point of the power MOSFETs 37 and 38 that are connectedin series in the upper arm 135 and the lower arm 136 are connected to anend portion of the W-phase coil of the armature winding 11 by means ofthe alternating-current wiring 21. A capacitor 22 is also connected inparallel between the upper and lower arms so as to smooth voltagefluctuations that result from switching of the power MOSFETs 37 and 38.A positive terminal and a negative terminal of a battery 23 areelectrically connected to a positive electrode side and a negativeelectrode side, respectively, of the control apparatus 130 by means ofdirect-current wiring 24. Moreover, the negative electrode of theautomotive electric motor-generator 101 and the negative electrode ofthe battery 23 may also be connected indirectly through separatepositions on a vehicle frame, etc.

In an automotive electric motor-generator 101 that is configured in thismanner, the control circuit 119 controls switching operations in thecontrol apparatus 130. The control circuit 119 also controls a fieldcurrent control circuit 26 so as to adjust a field current that issupplied to the field winding 7 of the rotor 6. In addition, the controlcircuit 119 has an inverter function for electric motor operation of theautomotive electric motor-generator 101 and a rectifying function forpower generation.

Here, during starting of an engine, direct-current power is suppliedfrom the battery 23 to the control apparatus 130 by means of thedirect-current wiring 24. The control circuit 119 that is mounted to thecontrol circuit board 120 performs on-off control of the power MOSFETs37 and 38 of the control apparatus 130 so as to convert thedirect-current power to three-phase alternating-current power. Thethree-phase alternating-current power is supplied to the armaturewinding 11 by means of the alternating-current wiring 21. Thus, arotating magnetic field is imparted around the field winding 7 of therotor 6 to which a field current is being supplied by the field currentcontrol circuit 26, driving the rotor 6 to rotate. Rotational torquefrom the rotor 6 is transmitted to the engine by means of the shaft 5,the pulley 13, and a belt (not shown) so as to ignite and start theengine.

Then, once the engine has been started, rotational torque from theengine is transmitted to the automotive electric motor-generator 101 bymeans of a crank pulley, the belt, and the pulley 13. Thus, the rotor 6is rotated, inducing a three-phase alternating-current voltage in thearmature winding 11. Then, the control circuit 119 performs on-offcontrol of the power MOSFETs 37 and 38 of the control apparatus 130 suchthat the three-phase alternating-current power that has been induced inthe armature winding 11 is converted into direct-current power, and issupplied to the battery 23, and an electric load 25, etc.

Next, configuration of the control apparatus 130 will be explained withreference to FIGS. 23 through 27.

A first radiating plate 139 is made of copper and has beenelectroplated, and is formed so as to have a shape that has: a flat baseportion 139 a that has an approximate fan shape (a C shape); and flangeportions 139 b that are disposed so as to extend radially outward from arear surface of the base portion 139 a at four positions that includetwo circumferential end portions of the base portion 139 a and portionsthat divide the base portion 139 a into three equal sectionscircumferentially. Twelve N-channel power MOSFETs 37 are mounted to thefirst radiating plate 139 so as to line up in a single rowcircumferentially such that source terminals 37S and gate terminals 37Gface radially outward by connecting drains thereof to a front surface (amounting surface) of the base portion 139 a using a lead-free solder. Inaddition, a plurality of ventilating apertures 151 a are disposed so asto pass through the base portion 139 a. Here, the power MOSFETs 37correspond to a first switching element.

A first circuit board 144 is prepared by insert molding six insertconductors 149 a through 149 f, and is formed so as to have a shape thathas: a flat base portion 144 a that has an approximate fan shape (a Cshape) that is parallel to an outer circumference of the base portion139 a of the first radiating plate 139; and flange portions 144 b thatare disposed so as to extend radially outward from a rear surface of thebase portion 144 a at four positions that include two circumferentialend portions of the base portion 144 a and portions that divide the baseportion 144 a into three equal sections circumferentially. The baseportion 144 a of the first circuit board 144 is disposed so as to beparallel to the outer circumference of the base portion 139 a of thefirst radiating plate 139, and the flange portions 144 b are disposed inclose contact with rear surfaces of the flange portions 139 a of thefirst radiating plate 139.

First through third radiating plate segments 141 through 143 are formedso as to have approximately identical sizes, are each made of copper andhave been electroplated, and are formed so as to have flat arc shapesthat are larger than the base portion 144 a of the first circuit board144. A plurality of ventilating apertures 151 b are disposed so as topass through the first through third radiating plate segments 141through 143. In addition, four N-channel power MOSFETs 38 are mounted toeach of the first through third radiating plate segments 141 through 143so as to line up in a single row circumferentially such that sourceterminals 38S and gate terminals 38G face radially outward by connectingdrains thereof to respective surfaces (mounting surfaces) using alead-free solder. The first through third radiating plate segments 141through 143 are arrayed in a single row circumferentially so as toconstitute a second radiating plate 140 that has an approximate fanshape (a C shape) that is larger than the base portion 144 a of thefirst circuit board 144. Here, the power MOSFETs 38 correspond to asecond switching element.

A second circuit board 145 is prepared by insert molding six insertconductors 150 a through 150 f, and is formed so as to have anapproximate fan shape (a C shape) that has: a base portion 145 a that isparallel to an outer circumference of the second radiating plate 140;and flange portions 145 b that extend radially inward from a rearsurface of the base portion 145 a at four positions that include twocircumferential end portions of the base portion 145 a and portions thatdivide the base portion 145 a into three equal sectionscircumferentially. Moreover, the insert conductors 150 a, 150 c, and 150e correspond to an electrode member that has negative potential.

The second circuit board 145 is disposed in an approximate fan shape soas to be centered around a central axis of the rear housing 3 such thatthe flange portions 145 b are placed in close contact with an endsurface of the rear housing 3. The first through third radiating platesegments 141 through 143 are also disposed so as to line up in anapproximate fan shape so as to be centered around the central axis ofthe rear housing 3 in close proximity to an inner circumferential sideof the base portion 145 a such that the mounting surfaces face axiallyoutward and two end portions of each are placed on the flange portions145 b. The mounting surfaces of the first through third radiating platesegments 141 through 143 are positioned in a common plane with a frontsurface of the base portion 145 a. In addition, the first circuit board144 is disposed such that the flange portions 144 b face the flangeportions 145 b of the second circuit board 145 across the first throughthird radiating plate segments 141 through 143. The first radiatingplate 139 is disposed such that the mounting surface of the base portion139 a faces axially outward, the flange portions 139 b are placed on theflange portions 144 b of the first circuit board 144, and the baseportion 139 a is in close proximity to an inner circumferential side ofthe base portion 144 a of the first circuit board 144.

The flange portions 139 b at three positions that are not at a secondcircumferential end portion of the first radiating plate 139, the flangeportions 144 b at three positions that are not at a secondcircumferential end portion of the first circuit board 144, firstcircumferential end portions of each of the first through thirdradiating plate segments 141 through 143, and the flange portions 145 bat three positions that are not at a second circumferential end portionof the second circuit board 145 are stacked axially on each other andsecurely fastened integrally to the rear housing 3 by mounting bolts147. In addition, an output terminal bolt 148 that constitutes anexternal output terminal is mounted so as to pass through the flangeportion 139 b at the second circumferential end portion of the firstradiating plate 139 from a rear surface side and project axially outwardthrough the cover 118. A terminal 146 is interposed between a headportion of the output terminal bolt 148 and the flange portion 139 b.The flange portion 144 b of the first circuit board 144 is interposedbetween the output terminal bolt 148 and the third radiating platesegment 143 such that the two are in an insulated state.

Thus, except at their respective first and second circumferential endportions, the first through third radiating plate segments 141 through143 are separated from a wall surface of the rear housing 3 by adistance equivalent to a thickness of the flange portions 145 b of thesecond circuit board 145 so as to form a cooling airflow ventilationchannel. The first radiating plate 139 and the first through thirdradiating plate segments 141 through 143 are also separated in an axialdirection of the shaft 5 by a distance equivalent to a total thicknessthat includes at least a thickness of the flange portions 144 b of thefirst circuit board 144 and a thickness of the flange portions 139 b ofthe first radiating plate 139 so as to form a cooling airflowventilation channel. In addition, the base portion 139 a of the firstradiating plate 139 is offset radially so as not to overlap with thefirst through third radiating plate segments 141 through 143 in an axialdirection of the shaft 5.

Two of the insert conductors 149 a and 149 c are insert-molded into thefirst circuit board 144 such that first ends are exposed at a firstcircumferential end portion front surface of the first circuit board144, and second end portions are exposed on surfaces in regions thatcorrespond to the source terminals 37S of the four power MOSFETs 37 thatconstitute the upper arms 131 and 135, respectively. Two of the insertconductors 149 b and 149 d are insert-molded into the first circuitboard 144 such that first ends are exposed at the first circumferentialend portion front surface of the first circuit board 144, and second endportions are exposed on surfaces in regions that correspond to the gateterminals 37G of the four power MOSFETs 37 that constitute the upperarms 131 and 135, respectively. Exposed surfaces of the second endportions of the insert conductors 149 a through 149 d are positioned ina common plane with the mounting surface of the first radiating plate139. The source terminals 37S and the gate terminals 37G of the fourpower MOSFETs 37 that constitute the upper arms 131 and 135 are solderedto the exposed surfaces of the corresponding insert conductors 149 athrough 149 d.

Two of the insert conductors 149 e and 149 f are insert-molded into thefirst circuit board 144 such that first ends are exposed at a secondcircumferential end portion front surface of the first circuit board144, and second end portions are exposed on surfaces in regions thatcorrespond to the source terminals 37S and the gate terminals 37G,respectively, of the four power MOSFETs 37 that constitute the upper arm133. Exposed surfaces of the second end portions of the insertconductors 149 e and 149 f are positioned in a common plane with themounting surface of the first radiating plate 139. The source terminals37S and the gate terminals 37G of the power MOSFETs 37 that constitutethe upper arm 133 are soldered to the exposed surfaces of thecorresponding insert conductors 149 e and 149 f.

Respective insert conductors 149 a, 149 c, and 149 e branch off and areexposed on the rear surfaces of the flange portions 144 b at threepositions that do not include the second circumferential end portion ofthe first circuit board 144. The exposed surfaces of these insertconductors 149 a, 149 c, and 149 e are placed in close contact with andelectrically connected to the first radiating plate segment 141, thethird radiating plate segment 143, and the second radiating platesegment 142, respectively, by the fastening force of the mounting bolts147.

Similarly, in the second circuit board 145, two of the insert conductors150 a and 150 c are insert-molded into the second circuit board 145 suchthat first ends are exposed at a first circumferential end portion frontsurface of the second circuit board 145, and second end portions areexposed on surfaces in regions of the base portion 145 a that correspondto the source terminals 38S of the four power MOSFETs 38 that constitutethe lower arms 132 and 136, respectively. Two of the insert conductors150 b and 150 d are insert-molded into the second circuit board 145 suchthat first ends are exposed at the first circumferential end portionfront surface of the second circuit board 145, and second end portionsare exposed on surfaces in regions of the base portion 145 a thatcorrespond to the gate terminals 38G of the four power MOSFETs 38 thatconstitute the lower arms 132 and 136, respectively. The sourceterminals 38S and the gate terminals 38G of the four power MOSFETs 38that constitute the lower arms 132 and 136 are soldered to the exposedsurfaces of the corresponding insert conductors 150 a through 150 d.

Two of the insert conductors 150 e and 150 f are insert-molded into thesecond circuit board 145 such that first ends are exposed at a secondcircumferential end portion front surface of the second circuit board145, and second end portions are exposed on surfaces in regions of thebase portion 145 a that correspond to the source terminals 38S and thegate terminals 38G, respectively, of the four power MOSFETs 38 thatconstitute the lower arm 134. The source terminals 38S and the gateterminals 38G of the power MOSFETs 38 that constitute the lower arm 134are soldered to the exposed surfaces of the corresponding insertconductors 150 e and 150 f.

Respective insert conductors 150 a and 150 c branch off and are exposedon the rear surfaces of the flange portions 145 b at two positions atthe first circumferential end portion of the second circuit board 145.In addition, an insert conductor 150 e branches off and is exposed onthe rear surfaces of the flange portions 145 b at two positions at thesecond circumferential end portion of the second circuit board 145. Theexposed surfaces of these insert conductors 150 a, 150 c, and 150 e areplaced in close contact with and electrically connected to the wallsurface of the rear housing 3 by the fastening force of the mountingbolts 147.

The control apparatus 130 that is configured in this manner is fastenedto the end surface of the rear housing 3 by the three mounting bolts 147so as to be disposed in an approximate fan shape radially outside theshaft 5. The control circuit board 120, to which the control circuit 119that includes elements such as custom ICs, drivers, etc., that controloperation of the power MOSFETs 37 and 38 is mounted, and the brushholder 14, into which the field current control circuit 26 and thecapacitor 22, etc., that control the field current to the field winding7 are integrated, are disposed in an approximately fan-shaped notchportion of the control apparatus 130.

The drains of the respective power MOSFETs 37 that constitute the upperarms 131, 133, and 135 are electrically connected to the output terminalbolt 148 by means of the first radiating plate 139 and are also led intothe brush holder 14 by means of the terminal 146. The source terminals38S of the respective power MOSFETs 38 that constitute the lower arms132, 134, and 136 are electrically connected to the rear housing 3 bymeans of the insert conductors 150 a, 150 c, and 150 e.

The source terminals 37S of the respective power MOSFETs 37 thatconstitute the upper arms 131, 133, and 135 are electrically connectedto the first through third radiating plate segments 141 through 143,respectively, by means of the exposed surfaces of the insert conductors149 a, 149 c, and 149 e that are exposed on the rear surfaces of theflange portions 144 b of the first circuit board 144. Output wires (thealternating-current wiring 21) of the U-phase coil, the V-phase coil,and the W-phase coil of the armature winding 11 are soldered to thefirst through third radiating plate segments 141 through 143,respectively.

The source terminals 37S and 38S and the gate terminals 37G and 38G ofthe power MOSFETs 37 and 38 are electrically connected to the controlcircuit 119 by means of the portions of the insert conductors 149 athrough 149 f and 150 a through 150 f that are exposed at thecircumferential end portions of the first and second circuit boards 144and 145.

Now, when the fan 12 at the rear end is driven to rotate together withthe rotation of the rotor 6, cooling airflows are sucked through the airintake apertures 118 a into the cover 118. The cooling airflows thathave been sucked into the cover 118 then flow in through the air intakeapertures 3 b into the rear housing 3, are deflected centrifugally bythe fan 12, and are discharged through the air discharge apertures 3 c.

Here, the cooling airflows flow as indicated by arrows Fa through Fd inFIG. 20. Specifically, as indicated by the arrow Fa, a cooling airflowthat has flowed in through the air intake apertures 118 a that aredisposed through the end surface of the cover 118 flows radially inwardover the front surface of the base portion 139 a of the first radiatingplate 139, and flows toward the rear housing 3 by passing between thefirst radiating plate 139 and the shaft 5. As indicated by the arrow Fb,a portion of the cooling airflow that has flowed in through the airintake apertures 118 a that are disposed through the end surface of thecover 118 flows toward the rear housing 3 by flowing between the firstradiating plate 139 and the second radiating plate 140.

In addition, as indicated by the arrow Fc, a cooling airflow that hasflowed in through the air intake apertures 118 a that are disposedthrough the side surface of the cover 118 flows toward the rear housing3 by flowing between the first radiating plate 139 and the secondradiating plate 140. As indicated by the arrow Fd, a portion of thecooling airflow that has flowed in through the air intake apertures 118a that are disposed through the side surface of the cover 118 flowsradially inward by flowing between the second radiating plate 140 andthe wall surface of the rear housing 3. The cooling airflows that haveflowed through the respective ventilation channels flow into the rearhousing 3 through the air intake apertures 3 b, are deflectedcentrifugally by the fan 12, and are discharged through the airdischarge apertures 3 c. The power MOSFETs 37 and 38, the first andsecond radiating plates 139 and 140, and the control circuit board 120,as well as the rear-end coil ends of the armature winding 11 and the airdischarge aperture ribs 3 a, are thereby cooled.

When the fan 12 at the front end is driven to rotate, cooling airflowsare sucked in through the air intake apertures 2 b into the fronthousing 2. The cooling airflows that have been sucked into the fronthousing 2 are deflected centrifugally by the fan 12, and are dischargedthrough the air discharge apertures 2 c. Front-end coil ends of thearmature winding 11 and the air discharge aperture ribs 2 a are therebycooled.

According to Embodiment 4, because the first radiating plate 139 and thesecond radiating plate 140 are disposed in two layers in an axialdirection of the shaft 5, the first and second radiating plates 139 and140 can be enlarged within the limited radial dimensions. Thus, becausethe surface areas and volumes of the first and second radiating plates139 and 140 for cooling the power MOSFETs 37 and 38 that generate alarge quantity of heat in the control apparatus 130 can be enlarged, thepower MOSFETs 37 and 38 can be cooled effectively without enlarging thecontrol apparatus 130. Thus, desired surface areas and volumes of thefirst and second radiating plates 139 and 140 can be ensured within thelimited radial dimensions, enabling reductions in the size of thecontrol apparatus 130.

Cooling airflow ventilation channels are formed between a front surfaceside of the first radiating plate 139 and the first radiating plate 139and the second radiating plate 140, and also between the secondradiating plate 140 and the wall surface of the rear housing 3. Thus,cooling can be improved because the cooling airflows flow over twosurfaces of the first radiating plate 139 and the second radiating plate140. Because accumulation of foreign matter and electrically conductivedeposits, etc., is avoided, the occurrence of leakage currents betweenthe different electric potentials, and galvanic corrosion, etc., canalso be prevented. In addition, because ventilation resistance isreduced, airflow rate can be increased and wind noise can also bereduced.

Because the first radiating plate 139 and the second radiating plate 140are offset in the radial direction of the shaft 5, cooling airflows thatflow axially are directed to the second radiating plate 140 withoutbeing obstructed by the first radiating plate 139. Thus, because thecooling airflows reach the second radiating plate 140 without beingwarmed by cooling the first radiating plate 139, cooling airflows thathave not been warmed are directed to the first radiating plate 139 andthe second radiating plate 140, improving cooling.

Because the ventilating apertures 151 a and 151 b are formed so as topass through the first and second radiating plates 139 and 140, coolingairflows that flow axially and radially flow through the ventilatingapertures 151 a and 151 b. Thus, because ventilation resistance isreduced, airflow rate can be increased, and wind noise can be reduced.

Because the output terminal bolt 148 projects axially outward from arear-end end portion of the automotive electric motor-generator 101,connecting wiring with the external components such as the battery 23,etc., is facilitated if space is present rearward in a vehicle.

Because the output terminal bolt 148 is mounted to the first radiatingplate 139, a flange portion 139 b for mounting the output terminal bolt148 is required on the first radiating plate 139, reducing the heatradiating area of the first radiating plate 139. However, because thefirst radiating plate 139 onto which the output terminal bolt 148 ismounted is positioned upstream from the second radiating plate 140 inthe axial direction of flow of the cooling airflows, deterioration incooling due to the reduction in heat radiating area is suppressed.

Here, it is desirable to make the radial width of the base portion 139 aof the first radiating plate 139 greater than the radial width of thebase portion of the second radiating plate 140. In that case, becausethe heat radiating area of the first radiating plate 139 is increased,cooling of the first radiating plate 139 is prevented from deterioratingdue to the output terminal bolt 148 being mounted. Thus, the coolingefficiency of the first radiating plate 139 becomes approximately equalto the cooling efficiency of the second radiating plate 140, enablingthe power MOSFETs 37 and 38 that are mounted to the first and secondradiating plates 139 and 140 to be cooled to approximately identicaltemperatures. In addition, because rigidity of the first radiating plate139 is increased, mechanical strength against external forces fromexternal connecting wires is improved. Thus, even if external forceswhen external components such as the battery 23, etc., are connected tothe output terminal bolt 148, or stresses that result from vibratingexternal forces, etc., act on the first radiating plate 139, situationsin which the first radiating plate 139 might break are prevented.

Because the first and second radiating plates 139 and 140 and the firstand second circuit boards 144 and 145 are fastened integrally onto theend surface of the rear housing 3 by the mounting bolts 147 in anassembled state, highly-reliable vibration resistance is achieved.

The second radiating plate 140 is fixed to the end surface of the rearhousing 3 by means of the flange portions 145 b of the second circuitboard 145 (an insulating member). Thus, because heat from the powerMOSFETs 38 is conducted to the rear housing 3 by means of the secondradiating plate 140 and the flange portions 145 b, the power MOSFETs 38can be cooled effectively.

The front surface of the base portion 145 a is positioned in a commonplane with the mounting surfaces of the first through third radiatingplate segments 141 through 143, the second end portions of the insertconductors 150 a through 150 f are exposed on the front surface of thebase portion 145 a at regions that correspond to the source terminals38S and the gate terminals 38G of the power MOSFETs 38, and the sourceterminals 38S and the gate terminals 38G of the power MOSFETs 38 aresoldered to the exposed surfaces of the corresponding insert conductors150 a through 150 f. Thus, the source terminals 38S and the gateterminals 38G of the power MOSFETs 38 and the insert conductors 150 athrough 150 f can be connected directly and simply, making reductions insize possible.

The insert conductors 150 a, 150 c, and 150 e that are electricallyconnected to the source terminals 38S of the power MOSFETs 38 areinsert-molded into the second circuit board 145 so as to be exposed onthe rear surfaces of the flange portions 145 b, and are placed incontact with the end surface of the rear housing 3 by the fasteningforce of the mounting bolts 147. Thus, connecting electrode members thatconnect the insert conductors 150 a, 150 c, and 150 e and the rearhousing 3 are no longer necessary, reducing the number of partsproportionately, and enabling weight, and cost, etc., to be reduced, andalso simplifying connecting processes. In addition, because the rearhousing 3 is used as ground for the automotive electric motor-generator101, electrode members that have negative potential are no longernecessary, reducing the number of parts, and enabling weight, and cost,etc., to be reduced. Because the source terminals 38S of the powerMOSFETs 38 are connected to the rear housing 3 by means of the insertconductors 150 a, 150 c, and 150 e, heat from the power MOSFETs 38 istransferred to the low-temperature rear housing 3 directly without airintervening, enabling temperature increases in the power MOSFETs 38 tobe suppressed.

Embodiment 5

FIG. 28 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 5 of thepresent invention, FIG. 29 is a rear-end end elevation, as seen from therear side, of the automotive electric motor-generator according toEmbodiment 5 of the present invention in a state in which a cover hasbeen removed, FIG. 30 is a plan that shows a control apparatus in theautomotive electric motor-generator according to Embodiment 5 of thepresent invention, FIG. 31 is a cross section that is taken along lineD-D in FIG. 29 so as to be viewed in the direction of the arrows, andFIG. 32 is a cross section that is taken along line E-E in FIG. 29 so asto be viewed in the direction of the arrows.

In FIGS. 28 through 32, a second circuit board 145A in a controlapparatus 130A is formed so as to have an approximate fan shape that hasan L-shaped cross section that is constituted by a base portion 145 aand a flange portion 145 b. First through third radiating plate segments141 through 143 that constitute a second radiating plate 140 are arrayedin an approximate fan shape, and are molded integrally with a secondcircuit board 145A such that front surfaces and inner wall surfaces ofeach are exposed. The front surfaces of the first through thirdradiating plate segments 141 through 143 that have been arrayed in anapproximate fan shape are positioned level with a front surface of thebase portion 145 a of the second circuit board 145A, and the rearsurfaces of the first through third radiating plate segments 141 through143 are covered by the flange portion 145 b.

Six insert conductors 150 a through 150 f are also insert-molded intothe second circuit board 145A, but instead of being exposed on a rearsurface of the flange portion 145 b, portions of the insert conductors150 a, 150 c, and 150 e extend radially outward from the base portion145 a in a vicinity of connecting protrusion portions 154 that aredisposed so as to protrude from an end surface of a rear housing 3.Projecting portions 152 of the insert conductors 150 a, 150 c, and 150 eare respectively fastened to the connecting protrusion portions 154 ofthe rear housing 3 by screws 153.

Moreover, the rest of this embodiment is configured in a similar mannerto Embodiment 4 above.

In this automotive electric motor-generator 101A, the second circuitboard 145A and the first through third radiating plate segments 141through 143 are disposed on the rear housing 3 in an approximate fanshape so as to be centered around the central axis of the rear housing3. The first circuit board 144 is disposed such that the flange portions144 b face the flange portion 145 b of the second circuit board 145Aacross the first through third radiating plate segments 141 through 143.In addition, the first radiating plate 139 is disposed such that theflange portions 139 b are placed on the flange portions 144 b of thefirst circuit board 144 and the base portion 139 a is in close proximityto an inner circumferential side of the base portion 144 a of the firstcircuit board 144.

The flange portions 139 b at three positions that are not at a secondcircumferential end of the first radiating plate 139, the flangeportions 144 b at three positions that are not at a secondcircumferential end portion of the first circuit board 144, firstcircumferential ends of each of the first through third radiating platesegments 141 through 143, and the flange portion 145 b of the secondcircuit board 145A are stacked axially on each other and securelyfastened to the rear housing 3 by mounting bolts 147. In addition, theoutput terminal bolt 148 is mounted so as to pass through the flangeportion 139 b at the second circumferential end of the first radiatingplate 139 from a rear surface side and project axially outward throughthe cover 118. The projecting portions 152 of the insert conductors 150a, 150 c, and 150 e are fastened to the connecting protrusion portions154 of the rear housing 3 by the screws 153. A terminal 146 isinterposed between a head portion of the output terminal bolt 148 andthe flange portion 139 b. In addition, although not shown, the flangeportion 144 b of the first circuit board 144 is interposed between theoutput terminal bolt 148 and the third radiating plate segment 143 suchthat the two are in an insulated state.

In an automotive electric motor-generator 101A that is configured inthis manner, the flange portion 145 b is placed in close contact withthe end surface of the rear housing 3 around an entire circumferentialregion of the second circuit board 145A, and the control apparatus 130Ais cooled by heat transfer through the flange portion 145 b of thesecond circuit board 145A to the rear housing 3, in addition to thecooling airflows Fa through Fc that are shown in FIG. 20.

In Embodiment 5, because the first and second radiating plates 139 and140 are disposed in two layers in an axial direction so as to be offsetfrom each other radially in a similar manner to Embodiment 4 above,ventilation resistance is also reduced, increasing the cooling airflowrate. Heat from the power MOSFETs 38 is transferred from the secondradiating plate 140 to the rear housing 3 by means of the flange portion145 b of the second circuit board 145A, and is cooled by the coolingairflows by means of the air discharge aperture ribs 3 a. Thus, becausethe flow rate of the cooling airflows is increased and the rate of heattransfer to the rear housing 3 is also increased, the rate of heatexchange from the rear housing 3 is increased by synergisticreinforcement of the two, suppressing temperature increases in thecontrol apparatus 130A.

Because the second radiating plate 140 (the first through thirdradiating plate segments 141 through 143) and the second circuit board145A are integrated by insert molding, highly-reliable vibrationresistance can be achieved, and the number of parts is also reduced,simplifying assembly.

The flange portion 145 b of the circuit board 145A is formed so as tohave an approximate fan shape. Thus, heat from the power MOSFETs 38 istransferred to the low-temperature rear housing 3 directly through thesecond radiating plate 140 and the flange portion 145 b, suppressingtemperature increases in the power MOSFETs 38. The first radiating plate139, the second radiating plate 140, and the first and second circuitboards 144 and 145A are also securely fastened such that a wide area ofthe approximately fan-shaped flange portion 145 b is placed in contactwith the end surface of the rear housing 3, achieving even morehighly-reliable vibration resistance.

Moreover, in conventional techniques, the drains and sources (grounds)of the lower arms are not in a common plane, spatially requiringconnecting members for connection and leading to increases in size.However, in Embodiment 5, the projecting portions 152 of the insertconductors 150 a, 150 c, and 150 e extend outward from the base portion145 a in the vicinity of the connecting protrusion portions 154 of therear housing 3 at an approximately uniform height. Thus, the lengths ofthe projecting portions 152 of the insert conductors 150 a, 150 c, and150 e are shortened, facilitating connection between the projectingportions 152 and the connecting protrusion portions 154. In other words,according to Embodiment 5, large connecting members that were requiredin conventional techniques are no longer necessary, enabling reductionsin size.

Embodiment 6

FIG. 33 is a longitudinal section that shows an overall configuration ofan automotive electric motor-generator according to Embodiment 6 of thepresent invention, FIG. 34 is a rear-end end elevation, as seen from therear side, of the automotive electric motor-generator according toEmbodiment 6 of the present invention, FIG. 35 is a rear-end endelevation, as seen from the rear side, of the automotive electricmotor-generator according to Embodiment 6 of the present invention in astate in which a cover has been removed, FIG. 36 is a plan that shows acontrol apparatus in the automotive electric motor-generator accordingto Embodiment 6 of the present invention, FIG. 37 is a cross sectionthat is taken along line F-F in FIG. 35 so as to be viewed in thedirection of the arrows, and FIG. 38 is a cross section that is takenalong line G-G in FIG. 35 so as to be viewed in the direction of thearrows.

In FIGS. 33 through 38, a first radiating plate 139A in a controlapparatus 130B is formed so as to have a shape that has: a flat baseportion 139 a that has an approximate fan shape that is similar to thatof a second radiating plate 140 that is formed by arraying first throughthird radiating plate segments 141 through 143 into an approximate fanshape; and flange portions 139 c that are disposed so as to project fromrear surface portions of the base portion 139 a at four positions thatinclude two circumferential end portions of the base portion 139 a andportions that divide the base portion 139 a into three equal sectionscircumferentially. In other words, thicknesses of portions of the baseportion 139 a at the flange portions 139 c are increased at rear surfaceportions. A first circuit board 144A is formed so as to have a shapethat has: a flat base portion 144 a that has an approximate fan shape (aC shape) that is parallel to an outer circumference of the base portion139 a of the first radiating plate 139A; and flange portions 144 b thatare disposed so as to extend radially outward from a rear surface of thebase portion 144 a at four positions that include two circumferentialend portions of the base portion 144 a and portions that divide the baseportion 144 a into three equal sections circumferentially.

Six insert conductors 149 a through 149 f are insert-molded into thisfirst circuit board 144A, and portions of the insert conductors 149 a,149 c, and 149 e are exposed on the rear surfaces of the flange portions144 b at three positions that do not include the second circumferentialend portion of the first circuit board 144. The exposed surfaces ofthese insert conductors 149 a, 149 c, and 149 e are placed in closecontact with and electrically connected to the first radiating platesegment 141, the third radiating plate segment 143, and the secondradiating plate segment 142, respectively, by the fastening force ofmounting bolts 147.

Air intake apertures 118 a are formed only in side wall surfaces of acover 118A, not in an end surface. The air intake apertures 118 a areformed in the cover 118A so as to be positioned radially outsiderespective positions that are on an opposite side of the first radiatingplate 139A from a rear housing, between the first radiating plate 139Aand the second radiating plate 140, and also near the rear housing fromthe second radiating plate 140.

Moreover, the rest of this embodiment is configured in a similar mannerto Embodiment 4 above.

In this automotive electric motor-generator 101B, the second circuitboard 145 is disposed on the rear housing 3 in an approximate fan shapeso as to be centered around the central axis of the rear housing 3, andthe first through third radiating plate segments 141 through 143 aredisposed so as to line up in an approximate fan shape so as to becentered around the central axis of the rear housing 3 in closeproximity to an inner circumferential side of the base portion 145 asuch that two end portions of each are placed on the flange portions 145b. The first circuit board 144A is disposed such that the flangeportions 144 b face the flange portion 145 b of the second circuit board145 across the first through third radiating plate segments 141 through143. In addition, the first radiating plate 139A is disposed such thatthe respective flange portions 139 c are placed on the flange portions144 b of the first circuit board 144A and the base portion 139 a is inclose proximity to an inner circumferential side of the base portion 144a of the first circuit board 144A.

The flange portions 139 c that are not at a second circumferential endportion of the first radiating plate 139A, the flange portions 144 b atthree positions that are not at a second circumferential end portion ofthe first circuit board 144A, first circumferential end portions of eachof the first through third radiating plate segments 141 through 143, andthe flange portions 145 b at three positions that are not at a secondcircumferential end portion of the second circuit board 145 are eachsecurely fastened to the rear housing 3 by the mounting bolts 147. Inaddition, an output terminal bolt 148 is mounted so as to pass throughthe flange portion 139 b at the second circumferential end portion ofthe first radiating plate 139A from a rear surface side. A terminal 146is interposed between a head portion of the output terminal bolt 148 andthe flange portion 139 b. The flange portion 144 b of the first circuitboard 144A is interposed between the output terminal bolt 148 and thethird radiating plate segment 143 such that the two are in an insulatedstate.

Thus, except at their respective first and second circumferential endportions, the first through third radiating plate segments 141 through143 are separated from a wall surface of the rear housing 3 by adistance equivalent to a thickness of the flange portions 145 b of thesecond circuit board 145 so as to form a cooling airflow ventilationchannel. The first radiating plate 139A and the first through thirdradiating plate segments 141 through 143 are also separated in an axialdirection of the shaft 5 by a distance equivalent to a total thicknessthat includes at least a thickness of the flange portions 144 b of thefirst circuit board 144A and a thickness of the flange portions 139 c ofthe first radiating plate 139A so as to form a cooling airflowventilation channel. In addition, the base portion 139 a of the firstradiating plate 139A overlaps with the second radiating plate 140 thatis constituted by the first through third radiating plate segments 141through 143 relative to an axial direction of the shaft 5.

In Embodiment 6, because the first and second radiating plates 139A and140 are also disposed in two layers in an axial direction, similareffects to those in Embodiment 4 above can be achieved.

Because the first and second radiating plates 139A and 140 are disposedso as to have similar radial positions, i.e., so as to overlap with eachother axially, and the air intake apertures 118 a are formed only inside wall surfaces of the cover 118A, cooling airflows that have flowedinside the cover 118A through the air intake apertures 118 a, flowradially inward on an opposite side of the first radiating plate 139Afrom a rear housing, between the first radiating plate 139A and thesecond radiating plate 140, and also near the rear housing from thesecond radiating plate 140, respectively, and flow into the rear housing3 through the air intake apertures 3 b. Thus, the heat radiating area ofthe first and second radiating plates 139A and 140 can be increasedwithout inhibiting radial flow of the cooling airflows. Because coolingairflows that have a temperature identical to that of the ambienttemperature flow radially inward to the first and second radiatingplates 139A and 140, highly-reliable cooling can be achieved. Inaddition, because the temperatures of the cooling airflows that aresupplied to the first and second radiating plates 139A and 140 areapproximately equal, the power MOSFETs 37 and 38 that are mounted to thefirst and second radiating plates 139A and 140 can be cooled toapproximately identical temperatures.

Because the first and second radiating plates 139A and 140 overlap witheach other axially, ventilation channels in which cooling airflows flowover the first and second radiating plates 139A and 140, flow to avicinity of the shaft 5, then flow through to the air intake apertures 3b are ensured in the vicinity of the shaft 5. Thus, because ventilationresistance is reduced, airflow rate is increased, improving cooling.

If high-temperature portions such as engine air discharge pipes, etc.,are disposed behind an automotive electric motor-generator, or largeoutput terminal mounts are mounted behind an automotive electricmotor-generator, etc., flow of the cooling airflows into the automotiveelectric motor-generator may be obstructed, making cooling poor.However, if this automotive electric motor-generator 101B is applied tocases in which a high-temperature portion such as an engine airdischarge pipe, etc., is disposed behind the automotive electricmotor-generator 101B, or cases in which a large output terminal mount ismounted behind the automotive electric motor-generator 101B, the engineair discharge pipe, or output terminal mount, etc., will not obstructthe radial flow of the cooling airflows, enabling superior cooling to beachieved.

Moreover, in Embodiments 4 through 6 above, the upper arms 131, 133, and135 and the lower arms 132, 134, and 136 are explained as being eachconfigured by connecting four power MOSFETs 37 or 38 in parallel, butthe number of power MOSFETs 37 or 38 in parallel is not limited to four,and is appropriately set so as to correspond to the required outputcapacity of the automotive electric motor-generator, and the maximumcapacity and permissible temperature of the semiconductor elements,etc., and the number of power MOSFETs 37 or 38 in parallel may also betwo or three, for example, or single power MOSFETs 37 or 38 may also beused.

In Embodiments 4 through 6 above, the output terminal bolt 148 ismounted so as to project axially outward, but an output terminal boltmay also be mounted so as to project radially outward.

1. An automotive electric motor-generator comprising: a motorcomprising: a rotor that is rotatably disposed inside a housing; astator that is disposed so as to surround a radially-outer side of saidrotor; and at least one fan that is fixed to an axial end surface ofsaid rotor, said motor functioning as a generator and as an electricmotor; and a power semiconductor apparatus that controls a current thatis supplied to said motor, characterized in that: said powersemiconductor apparatus comprises: a fan-shaped first radiating plate towhich a first switching element that is constituted by an N-channelsemiconductor element is mounted, and that has a drain potential forsaid first switching element; a fan-shaped second radiating plate towhich a second switching element that is constituted by an N-channelsemiconductor element is mounted, and that has a drain potential forsaid second switching element; a fan-shaped first circuit board in whicha first electrode member that connects said first switching element andsaid second switching element electrically in parallel is insert moldedinto a first insulating resin; and a fan-shaped second circuit board inwhich a second electrode member that is electrically connected to asource terminal of said second switching element and that has negativepotential is insert molded into a second insulating resin; wherein saidfirst radiating plate, said second radiating plate, said first circuitboard, and said second circuit board are disposed in a fan shape that iscentered around a shaft of said rotor so as to line up radially in aplane that is perpendicular to said shaft outside one axial end of saidhousing.
 2. An automotive electric motor-generator according to claim 1,characterized in that cooling airflow ventilation channels arerespectively ensured on an opposite side of said first and secondradiating plates from said housing, on a side of said first and secondradiating plates near said housing, and between said first and secondradiating plates when said fan is driven to rotate.
 3. An automotiveelectric motor-generator according to claim 1, characterized in thatventilating apertures are formed so as to pass axially through saidfirst and second radiating plates.
 4. An automotive electricmotor-generator according to claim 1, characterized in that said firstradiating plate is positioned on a radially inner side, and said secondradiating plate is positioned on a radially outer side.
 5. An automotiveelectric motor-generator according to claim 4, characterized in that anexternal output terminal is connected to said first radiating plate, andsaid first radiating plate is formed so as to have a radial width thatis wider than a radial width of said second radiating plate.
 6. Anautomotive electric motor-generator according to claim 1, characterizedin that said second radiating plate is configured such that threearc-shaped radiating plate segments that respectively correspond to eachof three phases are arrayed in a fan shape, a portion of said secondelectrode member is exposed from said second insulating resin so as tobe positioned in a common plane with a mounting surface of said secondswitching element on said three radiating plate segments in closeproximity to said three radiating plate segments, and a source terminalof said second switching element that is mounted to said three radiatingplate segments is connected to an exposed surface of said secondelectrode member.
 7. An automotive electric motor-generator according toclaim 6, characterized in that said second electrode member is connectedto said housing.
 8. An automotive electric motor-generator according toclaim 7, characterized in that said three radiating plate segments aremolded integrally with said second electrode member by said secondinsulating resin.
 9. An automotive electric motor-generator according toclaim 1, characterized in that said first and second insulating resinsare constituted by a single insulating resin, and said first radiatingplate and said second radiating plate are molded integrally with saidfirst and second electrode members by said single insulating resin. 10.An automotive electric motor-generator according to claim 1,characterized in that at least one of said first and second radiatingplates is fixed to said housing by means of said first insulating resinor said second insulating resin.
 11. An automotive electricmotor-generator comprising: a motor comprising: a rotor that isrotatably disposed inside a housing; a stator that is disposed so as tosurround a radially-outer side of said rotor; and at least one fan thatis fixed to an axial end surface of said rotor, said motor functioningas a generator and as an electric motor; and a power semiconductorapparatus that controls a current that is supplied to said motor,characterized in that: said power semiconductor apparatus comprises: afan-shaped first radiating plate that is disposed in a fan shape that iscentered around a shaft of said rotor in a plane that is perpendicularto said shaft outside a first axial end of said housing, to which afirst switching element that is constituted by an N-channelsemiconductor element is mounted, and that has a drain potential forsaid first switching element; and a fan-shaped second radiating platethat is disposed in a fan shape that is centered around said shaft in aplane that is perpendicular to said shaft of said rotor between saidfirst radiating plate and a first axial end surface of said housing, towhich a second switching element that is constituted by an N-channelsemiconductor element is mounted, and that has a drain potential forsaid second switching element.
 12. An automotive electricmotor-generator according to claim 11, characterized in that said firstand second radiating plates are disposed so as to be inmutually-different radial positions.
 13. An automotive electricmotor-generator according to claim 11, characterized in that coolingairflow ventilation channels are respectively ensured on an oppositeside of said first radiating plate from said housing, on a side of saidsecond radiating plate near said housing, and between said first andsecond radiating plates when said fan is driven to rotate.
 14. Anautomotive electric motor-generator according to claim 11, characterizedin that ventilating apertures are formed so as to pass axially throughsaid first and second radiating plates.
 15. An automotive electricmotor-generator according to claim 11, characterized in that an externaloutput terminal is connected to said first radiating plate.
 16. Anautomotive electric motor-generator according to claim 15, characterizedin that said first radiating plate is formed so as to have a radialwidth that is wider than a radial width of said second radiating plate.17. An automotive electric motor-generator according to claim 11,characterized in that said second radiating plate is configured suchthat three arc-shaped radiating plate segments that respectivelycorrespond to each of three phases are arrayed in a fan shape, a portionof an electrode member that has negative potential is disposed in acommon plane with a mounting surface of said second switching element onsaid three radiating plate segments in close proximity to said threeradiating plate segments, and a source terminal of said second switchingelement that is mounted to said three radiating plate segments isconnected to a portion of said electrode member.
 18. An automotiveelectric motor-generator according to claim 17, characterized in thatsaid electrode member that has negative potential is connected to saidhousing.
 19. An automotive electric motor-generator according to claim17, characterized in that said three radiating plate segments and saidelectrode member that has negative potential are molded integrally by aninsulating resin.
 20. An automotive electric motor-generator accordingto claim 11, characterized in that said second radiating plate is fixedto said housing by means of an insulating member.